title: Highly purified human peripheral blood monocytes produce IL-6 but not TNFalpha in response to angiotensin II.
abstract: OBJECTIVE
  Monocytes produce pro-inflammatory cytokines in response to Angiotensin II (AngII).
  
  
  BACKGROUND
  AngII has been suggested by many to be pro-inflammatory and likely to contribute to the migration of leukocytes in patients with cardiovascular conditions.
  
  
  METHODS
  Monocytes were purified from peripheral blood mononuclear cells (PBMCs) by negative selection using antibodies conjugated to magnetic beads. Detection of CD14(+) and AT(1)R expression was achieved by double-labeling flow cytometry. Highly purified monocytes were then stimulated with AngII (6 and 24 h) to assess IL-6 and TNF-α transcript levels by qRT-PCR and protein secretion by ELISA.
  
  
  RESULTS
  Monocytes comprised 9.7 ± 2.0% of the PBMCs. Monocyte isolation by negative selection yielded a purity of up to 99.8%. We demonstrated AT(1)R expression on 9.5 ± 0.3% of highly purifed CD14(+)/CD16(-) monocytes. Stimulation of highly purified monocytes with AngII resulted in increased transcript levels of IL-6 at 6 h but not at 24 h, and increased secretion of IL-6 in a dose-dependent manner compared with controls (p <0.01). Conversely, there was no increase in TNF-α mRNA transcripts or protein secretion.
  
  
  CONCLUSIONS
  We provide evidence that a CD14(+)/CD16(-) subset of highly purified human monocytes express AT(1)R and respond to AngII exposure in vitro by producing IL-6 but not TNF-α.
authors.affiliation: Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Laura
authors.initials: L
authors.lastname: Gelinas
authors.forename: Alec
authors.initials: A
authors.lastname: Falkenham
authors.forename: Adam
authors.initials: A
authors.lastname: Oxner
authors.forename: Mryanda
authors.initials: M
authors.lastname: Sopel
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Légaré
mesh_terms: D000328:Adult; D000804:Angiotensin II / Q000494:pharmacology*; D002469:Cell Separation; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000235:genetics; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008297:Male; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism; D017452:Receptors, IgG / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics
chemical_list: C508600:IL6 protein, human; D007375:Interleukin-1; D015850:Interleukin-6; D018950:Lipopolysaccharide Receptors; D012333:RNA, Messenger; D044140:Receptor, Angiotensin, Type 1; D017452:Receptors, IgG; D014409:Tumor Necrosis Factor-alpha; D000804:Angiotensin II